Free Radical Injury

Question 1

What does partial reduction (gain of an electron) of O2 yield?
(Gaining 1, 2, 3 and 4 electrons)

Answer 1

• O2-. (1 electron)
• H2O2 (2 electrons)
• OH (3 electrons)
• H2O (4 electrons)

Question 2

How can free radicals be generated pathalogically?

Answer 2

• Ionizing radiation
• Inflammation
• Metals (e.g coooer and iron)
• Drugs and chemicals (e.g acetaminophen)

Question 3

What is the most damaging free radical?

Answer 3

OH-

Question 4

What converts O2 to O2-. (superoxide)

Answer 4

NADPH oxidase

Question 5

What converts superoxide (O2-.) to hydrogen peroxide (H2O2)

Answer 5

Superoxide dismutase

Question 6

What converts hydrogen peroxide to bleach (HOCl)

Answer 6

Myeloperoxidase

Question 7

What free radical can be generated by iron?

Answer 7

OH-

Question 8

What does free radical damage due to acetominophen cause?

Answer 8

Liver necrosis

Question 9

What will free radicals do to lipids?

Answer 9

Peroxidation of lipids

Question 10

What will free radicals do to DNA and proteins?

Answer 10

Oxidation of DNA and proteins

Question 11

What substances can eliminate free radicals?

Answer 11

• Antioxidants (vit A, C, E)
• Enzymes
• Metal carrier proteins (transferrin)

Question 12

What enzymes eleminate free radicals?

Answer 12

• Super oxide dismutase (o2-. -> H2O2)
• Catalse (H2O2 -> OH)
• Glutathione peroxidase (OH -> H2O)

Question 13

What converts hydrogen peroxide (H2O2) to OH?

Answer 13

Catalase

Question 14

What converts OH to H2O?

Answer 14

Glutathione peroxidase

Question 15

Carbon tetrachloride (CCl4) is converted to carbon trichloride (CCl3.) by what enzyme and in what organ?

Answer 15

P450 in liver

Question 16

What is the effect of carbon trichloride in the cell?

Answer 16

Cellular swelling

- Rough endoplasmic reticulum will also swell and ribosomes will pop off -> reduces protein synthesis

Question 17

What proteins repackage fat and cholesterol in the liver and can then transport them out?

Answer 17

Apolipoproteins (prevents fatty liver)

- If fat cannot leave you will get fatty liver disease)

Question 18

What industry has exposure to CCl4 (carbon tetrachloride)?

- May cause fatty liver disease

Answer 18

Dry cleaning

Question 19

How does reperfusion damage tissues? (e.g myocytes after MI treated w. PCI)

Answer 19

Once blood returns oxygen and inflammatory cells will create free radicals which will continue injury
- Cardiac enzymes will increase after treatment